Technical guidelines on testing the migration of primary aromatic ...

Dwell volume0,9 ml4.3.3 HPLC calibrationThe calibration is performed by injecting the standard solutions into the HPLC underthe conditions described in 5.2. Because of the enrichment step (5.1) the standardsolutions represent migration solutions, which are 10fold lower concentrated.For every amine a calibration curve is constructed, plotting peak areas at thewavelengths with the highest adsorption against concentration values (dimensionμg/l).NOTE: The calibration curves should be linear and the correlation coefficient should be 0.995 orbetter.NOTE: Figure 1 shows a standard chromatogram with all analytesNOTE: Figure 2 gives an overview about correlation coefficients and maximal wavelengths.4.3.4 Confirmation of identity by diode array detectionThe spectra of the peaks are taken over the range of 210-400 nm and comparedwith the standard spectra. If the overlaid spectral profiles of the peaks are identicalwith the spectra of the standards, the identity of the substance is confirmed4.3.5 Evaluation of dataCalculation of analyte levelThe calculation is carried out with the method of external standard using the peakareas. The areas of the standards and the concentrations in the migration solutionsare subjected to a regression calculation. The result is a linear function:Specific migration (μg/l) = A + B x Area4.4 Precision of the data4.4.1 ValidationRepeatability and reproducibility- Standard deviations and recoveriesAcidic migration solutions of laminates were spiked with PAA standard solutions,worked up as described in 5.1 (concentrated sample solutions) and applied to HPLCaccording to 5.2. Calibration solutions with the same concentration of PAA as theconcentrated sample solutions were chromatographed as external standards (ESTD)in the same way.4.4.2 Detection limitsAqueous migration solutions of laminates were spiked with PAA standard solutionsand worked up according to 5.1. The detection limits were calculated by signal/noiseratio of 5:1, they are listed in figure 2.44